Abstract
In this paper, we revisit the high pressure behavior of by a combination of first-principle calculations, Raman spectroscopy and x-ray diffraction under high pressure. We confirm experimentally the cubic-to-tetragonal transition at and find no evidence for any other phase transition up to , the highest pressures investigated, at variance with past reports. We reinvestigate phase stability with density functional theory considering not only the known tetragonal () phase but also other potential antiferrodistortive candidates. This shows that the tetragonal phase becomes progressively more stable upon increasing pressure as compared to phases with more complex tilt systems. The possibility for a second transition to another tilted phase at higher pressures, and in particular to the very common orthorhombic structure, is therefore ruled out.
- Received 13 May 2022
- Revised 14 July 2022
- Accepted 15 July 2022
DOI:https://doi.org/10.1103/PhysRevB.106.064105
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